Flexible strip bus bar

ABSTRACT

A flexible strip bus bar for connecting a plurality of electrical contact posts, such as those found on a wire wrap board is disclosed. The invention comprises an elongated conducting strip of 0.008 berryllium copper, and has a number of biasing straps attached thereto for securing the strip and posts together. Preferably the straps are an integral part of the strips formed by pressing a portion of the face of the strip outwardly with a die. Insulation may be wrapped about any portion of the strip to be isolated from a post.

United States Patent 1191 Wyshak et al.

FLEXIBLE STRIP BUS BAR Inventors: Fred M. Wyshak, Marlboro;

William R. Lee, North Billerica; Harry L. Barrett, Jr., Wayland, all of Mass.

Assignee: 'Atlee Corporation, Woburn, Mass.

Filed: Sept. 6, 1974 Appl. No.1 503,90]

Related U.S. Application Data Continuation of Ser. No. 396,837, Sept. 13, 1973, abandoned.

U.S. Cl 339/19; 339/242 Int. Cl. HOIR 31/08 Field of Search 339/19, 278 C, 242;

24/81 CC, 129 B, 257 R, 259 C References Cited UNI-TED STATES PATENTS l/l954 Astleford.... 2/1966 Smith 339/258 14 1 Sept. 2, 1975 3,551,875 12 1970 Jarosek 339 19 3,582,864 6/1971 Sullivan 339 19 3,609,634 9/1971 Hovnanian.. 339 19 3,668,606 6/1972 Walter 339/19 Primary Exatn'inerRoy D. Frazier Assistant ExaminerRobert A. Hafer Attorney, Agent, or FirmJames J. Cannon. Jr.

[5 7] ABSTRACT 3 Claims, 6 Drawing Figures PATENTEDSEP ems FLEXIBLE STRIP BUS BAR CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of application Ser. No. 396,837, filed Sept. 13, 1973, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to electrical connectors and more particularly to bus bars for establishing a common ground or connection among a-plurality of electrical contacts such as wire wrap posts on circuit or terminal boards.

2. Description of the Prior Art The use of circuitor terminalboardswith corresponding wire wrap posts is well known in the field of electronics. The faces of such boards are arranged to receive electrical components or sub-assemblies at various terminals and the backs supplied with a post for each terminal, which posts are connected to one another to form completed electrical circuits according to the intended use of the board.

It is usually necessary to connect a number of these posts in series to form a common ground or other electrical connection for the circuit being constructed on the board. It is possible to do this in a number of ways, by direct wire wrapping, for example, the method used for harnessing the majority of the components of the board or by using special bus bars created just for the purpose of gang wiring to form a common ground.

Two such bars are disclosed in U.S. Pat. Nos. 3,488,620 and 3,582,864 wherein a full description of wire wrap terminal boards and the various techniques for wiring them as well as an exposition of bus bar devices is given.

In U.S. Pat. No. 3,488,620, a bar of unitary structure having an apex and two leg portions. is disclosed. Contact posts on a board pass between the arms and through the apex, the arms gripping the posts. This .device, in contrast to the invention described herein, does not appear to be flexible for application to contacts which are not all in a row, or suitable for application in situations in which particular posts in a row are skipped.

U.S. Pat. No. 3,582,864 discloses a barhaving a plurality of spring biased arms with axes running parallel to the conducting posts. As in the device above the posts pass through the apex of these arms. The present invention varys from this apparatus in the orientation of the arms, the method in which the arms and the strip relate, in simplicity of design and consequent ease and economy of manufacture and in other aspects which will become more evident from the summary which follows.

SUMMARY OF THE INVENTION The invention may be summarized as a new and improved electrically conducting bus bar for connecting a plurality of electrical contact posts in common relationship, such as a ground connection, on a terminal or wire wrap board. The bar is composed of an elongated strip of 0.008 beryllium copper having a number of post biasing straps spaced along its length for biasing the posts against the face of the strip. Preferably the strip is comprised of a flexible, bendable thin metal ribbon and the straps which may also be characterized as with the drawings.

arms or hooks are stamped, punched or pressed out from the face of the strip in a manner which leaves one or more ends of the strap attached to the strip or bar. The inherent spring-like quality of the .metal serves to grip the posts against the strip as they are pressed between'the strip.face and strap. This spring-like quality results from a heat treatment .of the strip to increase the temper of the berylliumn I Thus the insertion of the strip on a board is solderless, straightforward and easily-accomplished by workers engaged in assembling or wiringcircuit or terminal boards. The bar as described in the prefered embodiment may be bent 'to connect posts which are not all positioned in a straight row, an advantage over the prior art. Further, the design of the invention lends itself easily to the strap layout or spacing to conform to a particular circuit contact sequence during manufacwrapped with a loop of insulating material, preferably of heat shrinkable plastic, of a size sufficient to insulate the contact point. Thus, the bar may easily be wrapped with insulation at locations where posts would touch the strip but which have not been designated as part of the common circuit. The flexibility of the bar and orientation of the straps make it equally convenient to place tubular insulation over the posts.' 7

These and other advantages of the invention will become more evident from the following detailed'description of the prefered embodiment taken in conjunction DESCRIPTION OF THE DRAWINGS FIG. l'showing application of the bus bar'strip to a 'terminal board.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, there is shown a front view of a portion of the bus bar strip 10 which comprises the invention. The strip 10 is preferably a thin, highly conductive metal ribbon, manufactured of 8 mil beryllium copper for example. Optimally, the material used, as is i the above, is flexible and bendable to allow the strip to yllium. The bus bar strip may also be plated with tin or gold to resist corrosion and increase conductivity. Biasing straps 12 are shown attached at one end to the face of the strip 10 along edges 14. In this embodiment the straps 12 are formed by punching or pressing out a portion of material from the face of the strip 10. The natural springiness of the material used serves to bias the posts against the face of the strip 10 as will be seen from the additional figures of the drawing. This natural springiness, in the preferred embodiment, is obtained by'a heat treatment of the 8 mil beryllium copper which increases the temper of the beryllium.

Spacing is dictated by the distance between posts which for current standard terminal boards vary from 0.100 inches for posts of 0.025 inches thickness to 0.200 inches for posts of 0.045 inches thickness. The distance each strap 12 protrudes from the face depends upon the dimensions of the posts for the terminal board selected. This may vary from 0.025 to 0.045 inches in currently used boards, for example. These figures are only exemplary however, since the invention may obviously be applied to boards of any spacing and posts of any size. The flexible strip bus bar of this invention may be furnished in reels of up to one hundred feet in length with any desired strap spacing.

Normally ground connections which form the primary use of the invention are made to posts along one edge of the board and when necessary an additional edge at a right angle to the first edge. Circuit configurations sometimes require that a particular post in a position to touch the bus bar be bypassed and insulated from the bar. It is then desirable to eliminate the strap 12 in that position and to wrap that portion with insulation. In the instant embodiment this may be accomplished by. either clipping off or pounding down the protruding strap 12 or alternately, by not forming the strap 12 at all, that is, skipping that position in the manufacturing operation. Insulation 16, for example, a heat shrinkable tubular plastic material, is then slid to that position on the bus bar 10 and affixed. Optionally, of course, tubular insulation may be slid over the portion of the post itself that would come in contact with the strap 12 or bus bar strip 10.

FIG. 2 is a cross-sectional view of FIG. 1 taken along line AA showing the relation of the straps 12 to the bus bar strip 10. Strap 12 is punched out of a strip 10 in the profile illustrated leaving a space above portion 18 of the strip 10. The straps 12 pivot slightly at edge 14 in a spring-like manner to bias post 20 against strip 10.

FIG. 3 is an alternative construction of a strap 12 in which both ends 22 are left attached to the bus bar strip 10. As in FIG. 2, post 20 is biased against the bar 10 by the gripping action of the strap 12.

FIG. 4 is a front view of a bus bar strip 10 in which the straps 12 are arranged in two staggered rows. The design is the same as that contemplated and described for FIG. 1 except that this embodiment is more suitable for terminal boards in which the posts are spaced closely together. Areas 24 provide strength and conducting surface which would not be available if the straps 12 were in a single row as shown in FIG. 1.

FIG. 5 is a perspective view of the bus bar strip 10 of FIG. 1 inserted over a series of posts. The wire wrap posts are shown truncated and ordinarily will extend upward several times the width of the bar 10. Each post is either biased against the strip 10 by a strap 12 or insulated from it by insulator 16 as described above.

FIG. 6 illustrates the application of the invention to a terminal board prior to wire wrapping or otherwise electrically interconnecting the contact posts 20 on the back of the board 24. The face 26 of the board which receives electrical components is not visable. Here the bus bar strip 10 is applied by hand along two perpendicular rows of connectors 28 and 30 in the board assembly process. As is shown, it is only necessary to apply downward pressure along the bar 10 once the proper orientation of posts to be connected has been matched with the predetermined strip configuration. The strip 10 is bent at the edge 30 either prior to or during the application procedure.

As illustrated in the drawings, the manufacture of flexible bus bar strip 10 is relatively simple and inexpensive, even when strip 10 is custom-manufactured for particular spacing and connection requirements. In addition, the flexible, tempered quality of the preferred embodiment permits strip 10 to be rolled onto reels for ease of shipment, storage and dispensing in use, a distinct improvement over the prior art.

What is claimed is:

1. An electrically conducting bus bar for electrically connecting a plurality of spaced apart upright electrical contact posts comprising an elongated flexible, bendable thin metal ribbon made of heat treated beryllium copper, and a plurality of resilient hooks spaced along the longitudinal axis of said ribbon formed therein by pressed out substantially rectangular portions providing openings spaced therealong, said hooks comprising a first portion joined to said ribbon and extending perpendicular thereto, a second portion joined to the terminal end of said first portion and spaced from and extending parallel to said ribbon, and a third portion joined to the terminal end of said second portion and extending inwardly toward said ribbon at approximately a 45 angle and being substantially shorter than said first and second portions and having a free end in spaced relationship with said ribbon.

2. The apparatus of claim 1 wherein a portion of said strip is covered with insulating material over said strap a width at least the width of said contact post.

3. The apparatus of claim 1 wherein at least one of said straps is removed from said strip and the corresponding portion of said strip covered with insulating material a width at least the width of said contact port.

l l l 

1. An electrically conducting bus bar for electrically connecting a plurality of spaced apart upright electrical contact posts comprising an elongated flexible, bendable thin metal ribbon made of heat treated beryllium copper, and a plurality of resilient hooks spaced along the longitudinal axis of said ribbon formed therein by pressed out substantially rectangular portions providing openings spaced therealong, said hooks comprising a first portion joined to said ribbon and extending perpendicular thereto, a second portion joined to the terminal end of said first portion and spaced from and extending parallel to said ribbon, and a third portion joined to the terminal end of said second portion and extending inwardly toward said ribbon at approximately a 45* angle and being substantially shorter than said first and second portions and having a free end in spaced relationship with said ribbon.
 2. The apparatus of claim 1 wherein a portion of said strip is covered with insulating material over said strap a width at least the width of said contact post.
 3. The apparatus of claim 1 wherein at least one of said straps is removed from said strip and the corresponding portion of said strip covered with insulating material a width at least the width of said contact port. 